Container and method of making the same



Feb. 28, 1967 NscUM ET AL 3,306,200

CONTAINER AND METHOD OF MAKING THE SAME M MU m N A R B me Filed Nov. 20 19 United States Patent 3,306,200 CONTAINER AND METHOD OF MAKING THE SAME Tony E. Branscum, Winfield, Kans., and Estil N. Barnes,

Bartlesville, Okla, assignors to Phillips Petroleum Company, a corporation of Delaware Filed Nov. 20, 1964, Ser. No. 412,811 11 Claims. (Cl. 102-24) This invention relates to containers and to a method for making the same. In one of its aspects, the invention relates to a container for explosives. In another of its aspects, the invention relates to a container for explosives, which container is provided with a waterproof closure. In another aspect, the invention relates to containers for explosives which can be joined together by means of cooperating threaded portions of the container. Still another of its aspects, the invention relates to explosives containers having waterproof closure members which are joined together by a threaded engagement of the end of one container with an interior threaded member of the closure of another container. Yet another aspect of the invention, there is provided a method for producing or making a container wherein a thermoplastic material is blow molded to provide the essential parts of the container, a portion of the thus molded article is severed and inverted and then threaded into the open end of the article to close the article. In still another aspect of the invention, there is provided an explosive package wherein the afore-described container is filled with a suitable explosive.

Explosives are frequently used under conditions such that it is desirable or even necessary to exclude moisture or water from the explosive charge. As examples, mining operations frequently are performed under wet or moist conditions and yet it is necessary to use explosives as a part of the operation. Also, seismograph prospecting requires the use of explosives in drilled holes which, depending upon circumstances, may be filled with water. While it is true that some explosives are not particularly sensitive to the presence of moisture or water, other explosives such as ammonium nitrate are very sensitive.

Where explosives are used in small diameter drilled holes, the amount of explosive that can be used is governed by the length and the diameter thereof. If only a small charge is required, a short length of the explosive of the approximate diameter of the hole is sutficient. However, if a large charge is required, it is necessary to have a greater length of explosive. Where the explosive is shipped in packages of short length, it is necessary to join the packages together by some means. This is especially true in a vertical hole where it is frequently desirable to join all the lengths of the explosive above the surface of the ground and then to lower the explosive as a unit into the drilled hole. This practice is frequently followed in seismograph exploration.

The cost of explosives and the explosive container make up one of the largest single items of expenditure in such activities as mining and in seismograph exploration. Accordingly, it is desirable to utilize a low cost explosive and a low cost container for the same. Ammonium nitrate has been found to be a satisfactory low cost explosive and, where used, is usually mixed with a sensitizer such as an oil and packaged in a suitable container. However, ammonium nitrate must be protected from water.

Accordingly, it is an object of this invention to provide a low cost plastic explosives container which is waterproof under ordinary conditions. It is a further object of this invention to provide a container which by its unique construction is adapted to be joined to other similar containers to make an explosive charge of any desired length. A still further object of the invention is to provide a shipping and firing package comprising a container and a suitable explosive. Still another object of the invention is to provide a method for making a suitable low cost container for explosives. These and other objects, advantages, and features of the invention will be more clearly understood from a study of this disclosure, the drawing and the appended claims.

According to the invention, a hollow elongate cylinder having closed ends is formed, as by blow-molding a thermoplastic, whereby there is provided threaded portions at each end of the said cylinder and an intermediate threaded portion; the cylinder is converted to a container by severing a first threaded end and threading the same in reversed position into the said intermediate threads in sealing relation to the body of said cylinder; a plurality of such cylinders may be joined together in end to end relation by threading a second end of a similar container into the reversed first severed end of a first container. The containers are suitable for holding explosives and in particular water senstive explosives which are protected from damage by the seal provided. The threaded portions are so sized and contoured internally and externally of the hollow container so that of the three diameters of threads, those of the two end portions are adapted to engage and fit with at least one other thread either on the interior or exterior thereof. There is further provided wrench engaging means on at least one threaded end whereby threading of said end into a cooperating threaded portion is facilitated.

FIGURE I shows a container in of manufacture.

FIGURE II shows the intermediate article with one end severed.

FIGURE III shows a portion of the end of the closure member of the container.

FIGURE IV.shows a portion of the container where the severed end has been inverted and screwed into position.

Referring now to the drawing and to FIGURE I in particular, there is shown at 10 the container of our invention at an intermediate stage of manufacture. The container is preferably formed of a suitable thermoplastic material such as polyethylene, polypropylene, ethylene butene copolymers, polyvinyl chloride, or in fact any other suitable thermoplastic. Desirably, the container is formed in one step by blow molding. In the blow molding operation, a tube or parison of molten thermoplastic material is extruded downwardly between an open pair of mold sections. The mold sections are contoured on their interior to conform to the desired finished article. After a sufiicient length of the parison has been extruded, the mold sections close about the parison pinching it off at its top and bottom ends. According to a preferred method of blow molding, one of the mold sections is provided with a hollow needle which pierces the parison and air is admitted under pressure to inflate the parison within the mold sections causing it to conform to the interior contour of the mold. When the mold sections are opened, the tubular container which has cooled somewhat in the mold is removed from the mold sections. It is, of course, understood that a similar procedure could be used wherein vacuum is utilized and the vacuum is applied to the exterior of the parison or tube and air under atmospheric pressure is allowed to enter the interior of the parison by way of the hollow needle.

The container at the completion of the blow molding operation is provided with three separate sets of threads. These three sets of threads are so sized and so arranged that when the container is assembled for ultimate use, the three different sets of threads cooperate in a novel and an intermediate stage unique manner. The intermediate article is provided with a cylindrical body portion 11 which can be provided with shallow ridges as indicated at 12. Ridges 12 can be circular or helical or may have any other configuration. The ridges 12 are intended to provide a somewhat roughened surface so that the ultimate container can be held in hand without sliding through. At one end of the intermediate article there is provided a taper section 13 and a threaded section 14. Threads 14 are the smallest diameter of the three sets of threads provided. The other end of the intermediate article is provided with threads 16. Threaded sections 14 and 16 are closed, this having been accomplished by the pinching off of the parison by the mold sections when they were closed. Threaded section 16 is also provided with a wrench engaging means indicated at 17. As shown, the wrench engaging means is a square projection from the end closure of threaded section 16. However, it is to be mentioned that this projection could have some configuration other than square such as hexagonal. Also, it could be a recess instead of a projection.

Adjacent threads 16 and joining them to the main body 7 portion of the intermediate article is a tapered or conical section 20. Near the end of the body section 11, there is g,

provided a groove or recess, which groove is adapted to receive an O-ring as will be described subsequently. Adjacent groove 21 there are seen lines 22 and 22a which may be imaginary lines or which may be slight ridges or depressions molded onto the surface of the body 11. Be- :7 tween lines 22 and 22a is a small hole 23 representing the point at which the inflation needle pierced the parison. There is also provided on body portion 11 a thread indicated at 25.

To form a container from the intermediate article just described, all that is necessary is to sever one end from the article along the lines 22 and 22a and discard this small annular ring containing the blow hole. If desired, an O-ring may be installed in groove 21 and the thus severed end portion is reversed in direction and threaded into the interior of the open end of the article. There may be a very slight taper between the end of conical section 20 and severing line 22a. This taper can be adjusted to give the desired degree of interference fit between the severed section at the area adjacent to the O-ring groove and the main body of the article. It is seen that the exterior portion of threads 16 are so sized that these exterior threads mate with and engage the threads 25. If: an O-ring is installed (see 30, FIGURE IV) the O-ring will make a watertight seal between the threaded end portion and the body portion of the container. As just described, the threaded portion is now a closure for the assembled container.

FIGURE II shows one end of the intermediate article after the closure portion has been severed from the body portion.

FIGURE III illustrates the wrench receiving means of the end closure as shown at 17. As shown the wrench engaging means is square and is a projection from the end of the closure member, however, it should be borne in mind that the configuration could be hexagonal or any other desired shape and, of course, can be either a projection or a recess.

Referring now to FIGURE IV, there is shown one end of the container with the closure member inserted and an O-ring seal in place. FIGURE IV shows clearly the relationship between threads 25 and the exterior of threads 16 which are here shown threaded together. Positioned above the closure member there is shown one end of another container having threads 14. A plurality of containers may be joined together by threading the portion 14 into the interior of the closure member to threadedly engage the interior of threads 16. Any number of sections or containers can be joined together in this fashion. It is noted that threads 14 must have valleys and peaks of such a size as to properly engage the valleys and peaks of the interior portion of threads 16 and that the exterior portion of threads 16 must have valleys and peaks such as to properly engage the interior portion of threads 25. Since the closure member is wholly contained within the body portion, wrench engaging means 17 provides a convenient means for threading the sections together.

The container can be loaded with explosives at the site or it may be loaded with explosives at a manufacturing point and the loaded container shipped to the ultimate user. While the container could be used for some of the explosives which are not particularly sensitive to water such as dynamite, it finds greatest utility where the explosive is Water sensitive. Thus, the container can be filled with mixture of ammonium nitrate and oil and the closure member with seal ring will not only exclude water and moisture but also will prevent leakage of any of the contents.

When used in connection with seismographic explora= tion, a small diameter hole is drilled into the surface of the earth for the desired distance, and one or more of the containers with explosives is lowered into the hole. Where it is necessary to join a plurality of the containers together to obtain the required charge, this is conveniently done as the containers are being lowered. A first section of container is positioned over the hole and the second one threaded into the closure member. The grooves on the surface of the body member provide a convenient hand grip and the sections can be lowered hand-over-hand into the hole. As additional sections are threaded into the top most section, these too can be lowered by hand.

In the container illustrated in the drawing, a rubber O- ring sealing member 30 is shown. An O-ring need not be used to effect a seal. Numerous commercial adhesives and cements are available, any of which could be used to effect a seal when the closure member is inserted into the body member. A low temperature melting point asphalt or sealing cements such as are commercially used with gas= kets could be used. If some such resilient seal other than an O-ring is used, the groove 21 Can also be omitted if desired.

Reasonable variation and modification are possible within the scope of the invention, the essence of which is that there is provided a hollow container and shipping package for explosives and method for making the same, which container comprises a tubular body portion, a threaded end portion, and internal thread, and a threaded closure member for cooperatively engaging the said internal thread and for receiving the threaded end portion of another container.

We claim:

1. An article of manufacture comprising (a) a hollow cylindrical body of thermoplastic material having a length greater than its diameter and being closed at each of its ends;

(b) external threads on a first end of said body, said external threads being of a diameter less than that of said body;

(c) external and internal threads on a second end of said body, said external and internal threads being formed so that the valleys of the external thread are the peaks of the internal thread portion, said external and internal threads beings of a diameter such that the external threads of item (b) above could be fitted interiorly thereof;

(d) a circumferential groove adapted to receive a a packing ring adjacent the said second end of said body and positioned on a flat portion of the surface of the said body;

(e) an interior thread in said body spaced from but adjacent the said circumferential groove, said interior thread being of a size such that the external threads of the second end of said body could be fitted interiorly therein;

(f) and a series of deformations along the remaining a length of said body.

2. An article of manufacture adapted to be converted into a container comprising a cylindrical member having a central body portion, first and second threaded end portions and an intermediate threaded portion, said first threaded end portion having a diameter less than any of the other threaded portions, said second end portion having a diameter greater than said first end portion and said intermediate threaded portion having a diameter greater than said second end portion, said threaded portions being of a nature such that if separated, the first threaded portion would screw into and fit the interior of said second end portion, and said second end portion would screw into and fit said intermediate threaded portion.

3. A shipping and firing container for explosives and the like comprising in combination:

(a) a cylindrical body member having an open end, a closed end, a tapered section near said closed end, and external threads on the said closed end;

(b) internal threads in said body spaced from but near the said open end of said body;

(c) a closure member comprising a hollow short cylindrical section having a circumferential groove, a tapered section, a closed threaded end portion having both external and internal threads wherein the valleys of the external threads coincide with the peaks of the internal threads, and wrench engaging means on the closed end of said closure member, the external threads of said closure being adapted to engage the internal threads of said cylindrical body member and the internal threads of said closure being adapted to engagingly receive the external threads of the closed end portion of another container;

( d) and a resilient sealing means in said circumferential groove adapted to make a leakproof seal when said closure member is installed in said body member.

4. An article of manufacture comprising (a) a hollow tubular body having a length greater than its cross-sectional dimension and being closed at each of its ends;

(b) external threads on a first end of said body, said external threads being of a diameter less than that of said body;

(c) a tapered portion intermediate said threaded portion and said body member;

(d) external and internal threads on a second end of said body, said external and internal threads being formed so that the valleys of the external thread are the peaks of the internal thread portion, said internal threads being of a diameter such that the external threads of item (b) above could be fitted exteriorly thereof;

(e) a tapered portion intermediate said second threaded end portion and said body;

(f) a circumferential groove adapted to receive a packing ring adjacent the tapered portion of said second end and positioned on a flat portion of the surface of the said body;

(g) an interior thread in said body spaced from but adjacent the said circumferential groove, said interior thread being of a size such that the external threads of the second end of said body could be fitted interiorly therein;

(h) and a wrench engaging means positioned in the closed end portion of said second end.

5. The article of claim 4 further comprising a series of grooves along the external portion of at least the central portion of said body.

6. A shipping and firing container for explosives and the like comprising in combination:

(a) a tubular body member having an open end, a

closed end, a tapered section near said closed end, and external threads on the said closed end;

(b) internal threads in said body spaced from but near the said open end of said body;

(c) a closure member comprising a short cylindrical section having a circumferential groove, a tapered section, a closed threaded end portion having both external and internal threads wherein the valleys of the external threads coincide with the peaks of the internal threads, the external threads of said closure being adapted to engage the internal threads of said tubular body member;

(d) and a resilient sealing means in said circumferential groove adapted to make a leakproof seal when said closure member is installed in said body member.

7. A container according to claim 6 wherein said body member is further provided with a plurality of surface deformations along at least a part of its length.

8. The container according to claim 6 wherein the said container is formed of a thermoplastic material.

9. An explosive package containing in combination:

(a) a container comprising a tubular body member having a first threaded end, a second end having a threaded closure member threadedly engaged into a second end of said container, said closure member also having interior threads adapted to receive the threaded end of another container and sealing means between said closure member and said tubular body;

(b) and an explosive in said container.

10. The explosive package according to claim 9 wherein the explosive within the said container is a mixture of ammonium nitrate and an oil.

11. A shipping and firing container for explosives and the like comprising in combination:

(a) a cylindrical body member having an open end,

a closed end, a tapered section near said closed end, and external threads on the said closed end;

(b) internal threads in said body spaced from but near the said open end of said body;

(0) a closure member comprising a short cylindrical section, a tapered section, a closed threaded end portion having both external and internal threads wherein the valleys of the external threads coincide with the peaks of the internal threads, and wrench engaging means on the closed end of said closure member, the external threads of said closure being adapted to engage the internal threads of said cylindrical body member and the internal threads of said closure being adapted to engagingly receive the external threads of the closed end portion of another container;

(d) and a resilient sealing material between said closure member and said body member, said material being adapted to make a leakproof seal when said closure member is installed in said body member.

References Cited by the Examiner UNITED STATES PATENTS 1,081,555 12/1913 Russell 220-27 2,183,691 12/1939 Owens 264-159 2,503,171 4/1950 Posner 264-159 2,887,953 5/1959 Mager 102-24 3,013,492 12/1961 Sexton 102-24 3,025,988 3/1962 Williams 220-27 X 3,036,523 5/1962 Lea 102-24 3,049,079 8/1962 Eilo 102-24 3,156,350 11/1964 Lockwood 206-46 3,185,092 5/1965 Hamilton 102-24 3,190,441 6/1965 Rausing 206-46 3,195,928 7/ 1965 Pasternack 102-24 X BENJAMIN A. BORCHELT, Primary Examiner.

R. V. LOTIMANN, V. R. PENDEGRASS,

Assistant Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,306,200 February 28, 1967 Tony E. Branscum et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 51, for "exteriorly" read interiorly Signed and sealed this 7th day of November 1967.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

9. AN EXPLOSIVE PACKAGE CONTAINING IN COMBINATION: (A) A CONTAINER COMPRISING A TUBULAR BODY MEMBER HAVING A FIRST THREADED END, A SECOND END HAVING A THREADED CLOSURE MEMBER THREADEDLY ENGAGED INTO A SECOND END OF SAID CONTAINER, SAID CLOSURE MEMBER ALSO HAVING INTERIOR THREADS ADAPTED TO RECEIVE THE THREADED END OF ANOTHER CONTAINER AND SEALING MEANS BETWEEN SAID CLOSURE MEMBER AND SAID TUBULAR BODY; (B) AND AN EXPLOSIVE IN SAID CONTAINER. 